On the evaluation of displacement and deformation in tidal waves according to digital records of STS-2 and KSESh-R seismometers

A procedure for eliciting displacements in tidal waves from seismograms of broadband velocimeters like STS-2 and KSESH-R and the evaluation conversion of these displacements into vertical or volumetric deformation is proposed.     

Recovery of long-period ground vibrations from short-period seismometer records

The possibilities of recovering long-period ground vibrations from the records of short-period seismometers, geophones, and vibration sensors are considered. The procedures of recovering vibrations with periods equal to several minutes and several hours from initial seismograms recorded by short-period seismometers are presented.     

Response of Water-Saturated Reservoirs to a Dynamic Impact Based on the Data of Groundwater-Level Monitoring by Precision Measurements

Izvestiya, Physics of the Solid Earth - Abstract—Deformation regimes of water-saturated reservoirs under dynamic impact are studied using groundwater-level monitoring by precision...     

Groundwater level monitoring by precision measurements

The paper presents the results of processing the data on variations of groundwater level in an aquifer opened by a well in a depth interval of 76–115 m. The obtained series are compared with the volume deformation of the aquifer, calculated theoretically using the ETERNA 3.0 tidal analysis program. Two components are detected in the long-period area: the one coherent to the luni-solar tides and the one incoherent to them. It is established that the phase shift between the variations of volume deformation of the aquifer and the corresponding variations of water level in the well depends not only on the stressed-deformed state of the surrounding rock massif, but on the position of the piezometric surface of the aquifer as well. Some peculiarities of the effects of luni-solar tides on variations of groundwater level are considered. The amplitudes of groundwater level and volume deformation of the aquifer, as well as the phase shift between these parameters are estimated for the detected tidal waves. The value of the amplitude factor lies in the range of 0.04–0.058 cm/nanostrain.     

Correction of frequency characteristics of seismic sensors and noise of corresponding measuring channels

The paper has assessed the noise of the measuring channel, which includes a seismic receiver, preliminary amplifier, and correction filter (this filter broadens the frequency characteristics of the seismic receiver into the low frequencies range). The correction, mainly from the preliminary amplifier, contributes an additional noise into the measuring channel, therefore application of corrected seismometers and geophones is restricted by the class of signals that provide a signal-to-noise ratio of no less than 3–5. Such signals are seismic waves from regional earthquakes and industrial blasting.     

Rationale for applying short-period sensors with extended frequency response for recording strong earthquakes

The article proves the application of short-period sensors with extended frequency response as a reasonable alternative to broadband seismometers. We assessed uncertainties between magnitudes determined by short-period and broadband sensor data for earthquakes with M > 6 recorded at the Mikhnevo geophysical observatory in 2014. Data analysis consisted of body wave magnitude and surface wave magnitude estimates by standard seismological methods. Magnitude errors corresponded to the magnitude uncertainties in seismological catalogs.